Thanks for the ref LFAJ. However, the text in my copy (4th Ed) does not answer my questions, nor clarify what the markings actual consist of – not a zig zag in any of the diagrams.
Could it be assumed that the zigzags are a replacement for existing aiming point markings (#2) - there is less white paint than previously (Annex 14, fig 5.5), which are a nominal 400m from the threshold on a long runway?
If so, we have always lived with the disparity in aiming / touchdown, PAPI/ILS, etc, where the markings might not have been interpreted / used in any particular way.